From fbb36bc94ac6eaba7fd346314a9c43d27cb5348d Mon Sep 17 00:00:00 2001
From: bel <me@me.me>
Date: Sat, 1 Feb 2020 22:24:08 +0000
Subject: [PATCH] Add restore, backup, list, and clean commands

---
 README.md |   0
 main.go   | 109 ++++++++++++++++++++++++++++++++++++++++++++++++------
 2 files changed, 98 insertions(+), 11 deletions(-)
 mode change 100644 => 100755 README.md
 mode change 100644 => 100755 main.go

diff --git a/README.md b/README.md
old mode 100644
new mode 100755
diff --git a/main.go b/main.go
old mode 100644
new mode 100755
index 061d52c..f97e821
--- a/main.go
+++ b/main.go
@@ -1,7 +1,9 @@
 package main
 
 import (
+	"bytes"
 	"fmt"
+	"io"
 	"io/ioutil"
 	"local/args"
 	"local/storage"
@@ -21,20 +23,42 @@ type Config struct {
 	ns     string
 	root   string
 	store  string
+	cmd    string
+}
+
+type LastN struct {
+	store storage.DB
+	conf  Config
 }
 
 func main() {
 	conf := config()
 	log.Println(conf)
-	store, err := storage.New(storage.TypeFromString(conf.store), conf.conf, path.Join(conf.rclone+":", conf.ns))
+	storage, err := storage.New(storage.TypeFromString(conf.store), conf.conf, path.Join(conf.rclone+":", conf.ns))
 	if err != nil {
 		panic(err)
 	}
-	if err := push(conf.root, store); err != nil {
-		panic(err)
+	lastn := &LastN{
+		conf:  conf,
+		store: storage,
 	}
-	if err := clean(conf.n, store); err != nil {
-		panic(err)
+	actions := []func() error{}
+	switch conf.cmd {
+	case "backup":
+		actions = append(actions, lastn.push, lastn.clean)
+	case "list":
+		actions = append(actions, lastn.list)
+	case "clean":
+		actions = append(actions, lastn.clean)
+	case "restore":
+		actions = append(actions, lastn.restore)
+	default:
+		panic(fmt.Sprintf("not impl: %s"))
+	}
+	for _, action := range actions {
+		if err := action(); err != nil {
+			panic(err)
+		}
 	}
 }
 
@@ -46,20 +70,28 @@ func config() Config {
 	as.Append(args.STRING, "ns", "ns for backups", path.Join("lastn", "dev"))
 	as.Append(args.STRING, "rclone", "rclone backend name", "blapointe-drive-enc")
 	as.Append(args.STRING, "store", "type of store, like [map rclone]", "map")
+	as.Append(args.STRING, "cmd", "[backup, restore, list, clean]", "backup")
 	if err := as.Parse(); err != nil {
 		panic(err)
 	}
+	root, err := filepath.Abs(as.Get("root").GetString())
+	if err != nil {
+		panic(err)
+	}
 	return Config{
 		n:      as.Get("n").GetInt(),
 		conf:   as.Get("conf").GetString(),
 		rclone: as.Get("rclone").GetString(),
-		root:   as.Get("root").GetString(),
+		root:   root,
 		ns:     as.Get("ns").GetString(),
 		store:  as.Get("store").GetString(),
+		cmd:    as.Get("cmd").GetString(),
 	}
 }
 
-func push(root string, store storage.DB) error {
+func (lastN *LastN) push() error {
+	root := lastN.conf.root
+	store := lastN.store
 	root, err := filepath.Abs(root)
 	if err != nil {
 		return err
@@ -73,11 +105,11 @@ func push(root string, store storage.DB) error {
 	)
 	cmd := exec.Command(
 		"tar",
-		"-C",
-		path.Dir(root),
 		"-czf",
 		archive,
-		root,
+		"-C",
+		path.Dir(root),
+		path.Base(root),
 	)
 	out, err := cmd.CombinedOutput()
 	if err != nil {
@@ -91,7 +123,9 @@ func push(root string, store storage.DB) error {
 	return store.Set(path.Base(archive), b)
 }
 
-func clean(n int, store storage.DB) error {
+func (lastN *LastN) clean() error {
+	n := lastN.conf.n
+	store := lastN.store
 	backups, err := store.List(nil)
 	if err != nil {
 		return err
@@ -106,3 +140,56 @@ func clean(n int, store storage.DB) error {
 	}
 	return nil
 }
+
+func (lastN *LastN) list() error {
+	store := lastN.store
+	backups, err := store.List(nil)
+	if err != nil {
+		return err
+	}
+	sort.Strings(backups)
+	for _, backup := range backups {
+		log.Println(backup)
+	}
+	return nil
+}
+
+func (lastN *LastN) restore() error {
+	root := lastN.conf.root + "-restore"
+	os.RemoveAll(root)
+	if err := os.MkdirAll(root, os.ModePerm); err != nil {
+		return err
+	}
+	store := lastN.store
+	backups, err := store.List(nil)
+	if err != nil {
+		return fmt.Errorf("cannot list: %v", err)
+	}
+	sort.Strings(backups)
+	backup := backups[len(backups)-1]
+	b, err := store.Get(backup)
+	if err != nil {
+		return fmt.Errorf("cannot get %s: %v", backup, err)
+	}
+	log.Printf("restoring %s (%v) in %s", backup, len(b), root)
+	cmd := exec.Command(
+		"tar",
+		"-C",
+		root,
+		"-xzf",
+		"-",
+	)
+	stdin, err := cmd.StdinPipe()
+	if err != nil {
+		return fmt.Errorf("cannot get stdin: %v", err)
+	}
+	go func() {
+		defer stdin.Close()
+		io.Copy(stdin, bytes.NewReader(b))
+	}()
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		return fmt.Errorf("failed tar -xf: %v: %s", err, out)
+	}
+	return nil
+}